But paddle closer, and the 36-year-old may share some darker stories. Like the time he experienced psychosis during a work trip to Mexico, and seriously considered ending his own life.

Or the day he had to scarper from a work presentation because of sky-high anxiety. And the many times his bipolar was misdiagnosed as anxiety and depression.

Then there was the week-long manic episode when he broke up with his long-term girlfriend, spent all his money on bar tabs, went to work dressed as a tequila farmer and quit his marketing job. It ended when he stole a rescue board at a surf competition and was handcuffed in front of hundreds of people and taken to Manly Hospital's mental health ward.

"I thought I was having the time of my life and it wasn't until I got handcuffed and taken to the mental health ward that it all kind of came crashing down," says the New Zealand-born Sydneysider.

Talking about his experiences has become the norm for Trebilco, who four years ago founded a non-profit movement known as OneWave, which runs regular events known as 'Fluro Friday'.

The idea is that surfers come together, dressed in fluro, to share their stories and enjoy the soothing effects of surfing.

"I thought fluro, it makes people happy, but it also makes an invisible issue visible," says Trebilco. "It gets people asking questions about mental health." 

He and mate Sam Schumacher, a surfing instructor who studied aerospace engineering, have helped build Fluro Friday into a global phenomenon that's spread to more than 100 beaches in over 20 countries.

Trebilco says his 10 days in the mental health ward – the worst experience of his life – inspired the idea.

"I was just angry at the world," he says. "But it was in there that I started to think – shit – well at least I know I've got bipolar. At least I don't have to hide it any more."

Trebilco, incredibly bored, started chatting to other patients to try and understand what they were going through.

"I just kind of found everyone was fighting a battle they knew nothing about," he says. "We kind of all yarned and it all helped me a lot."

On day seven, he was allowed out for an hour, so his family arrived and raced him to the surf, where Trebilco found a glimmer of hope for his future.

After being released from hospital, he returned to New Zealand for six months, where his family cared for him and he surfed and surfed – sometimes up to six hours a day.

"I couldn't sit still on the couch for longer than a couple of minutes, because the anxiety was so bad from the medication that I was trying out. But I could sit in the ocean for hours."

Eventually, Trebilco decided that living with bipolar would be much easier if he told his mates. But it was tough.

"I told my best mate out in the surf and I was shitting myself," he says. "For some reason I thought he might think it's a weakness and treat me differently. But he just gave me a hug and said 'man, I've got your back no matter what'."

Emboldened, Trebilco dressed in an unorthodox surfing get-up – board shorts, a business shirt and a tie – and hit Bondi Beach one Friday morning for a 'board meeting', hoping that it would encourage other surfers to strike up a conversation.

Many simply laughed, but one surfer started chatting and Trebilco shared his story.

"He kind of sat there silent for a bit and then you could see in his eyes that it meant something to him," says Trebilco. His new acquaintance revealed he'd been suffering depression for years, but had never told anyone.

"It was two guys like tearing up in the surf and I was like if this is all it takes, me dressing up like an idiot every week and going surfing to get people to talk about mental health, then l'm going to do it for the rest of my life," says Trebilco.

That first outing soon morphed into Fluro Friday, which this Friday will mark its fourth anniversary with surfers gathering at more than 50 beaches globally to mark the milestone.

Meanwhile, its founder has largely learnt to live with his bipolar, but says anxiety raises its head regularly between the highs and lows. Just after he launched OneWave, Trebilco got so excited that he couldn't sleep and wound up back in hospital.

He's now an in-demand speaker, spreading the word at schools and corporate workplaces including Westpac, LinkedIn and RedBalloon.

Trebilco, who hasn't missed a single Fluro Friday in four years, says he probably would "have been screwed without surfing".

"But once you get out there…it's like the saltwater just rinses off all the bad vibes and it makes everything that little bit easier." 

Click here for more information on Fluro Friday. 

Executive Style